The present invention relates, in general, to amplifiers and, more particularly, to power amplifier circuits.
Portable communication devices include cellular phones and two-way radios. An important component of these devices is the power amplifier circuit. Performance parameters of the power amplifier circuit include linearity and efficiency. The linearity of the power amplifier circuit affects the quality of a signal transmitted by the portable communication device. The efficiency of a power amplifier circuit affects battery life, size, and weight of the portable communication device. Thus, it is desirable for a power amplifier circuit used in these devices to have a large linear range of operation. However, power amplifier circuits having a large linear range of operation are inherently inefficient.
Accordingly, it would be advantageous to have a power amplifier circuit that is both linear and efficient. It would be of further advantage for the power amplifier circuit to be area and cost efficient.